Cleaning an old keyboard... with a difference

[Muzer]

As I mentioned in my other thread, the Apricot Xi I bought has some keys you have to press very hard, and some that don't work at all. Looking under the hood, it isn't hard to see why:

All the conductive material that touches the contacts together is actually some metal foil attached to foam pads (possibly aluminium foil, but don't quote me) - which has oxidised rather badly in places. In other paces, the foam has been squished down with use.

So, what would be the best way to go about fixing this? I've been considering glueing extra aluminium foil onto the problem keys, and possibly supplementing the foam on some of the others - but I'm wondering if that will last, and if there would be a better way.

I would also give the contacts a bit of a clean - although they are not as bad as the pads, they have tarnished slightly.

 

[PymerOne]

Dear Muzer,

i am not gone tell you to microswitch each and every key
Patches of doublesided foamtape with tinfoil/aluminiumfoil around them sounds more doable.
Cleaning the tarnished contacts might be a tricky job...the foam could absorb the cleaningfluid and get eaten by that over time.
Goodluck,

Grtz, PymerOne.

 

[Merlin]

That foam reminds me of the insulation that you can put between joists that has an aluminium reflective coating laminated onto it. Normal aluminium foil won't be durable enough to last and conductive paint may dissolve the foam. Disposable aluminium pie trays are more like the thickness you need, but cutting lots of circles out would be a pain....

Maybe the answer to your problem lies in the plumbing department of your local DIY superstore, as there may be a flexible laminated aluminium/foam material there for lagging pipes or tanks?

A more permanent fix would be to solder a mouse button microswitch on each set of contacts, but that depends on cost and the clearance under the keys.

 

[Muzer]

Oh, I've just realised something I hadn't noticed before. The pads appear to actually be metal-plated clear plastic discs. They haven't oxidised at all - the metal has actually rubbed off and the green you can see is the foam underneath!

 

[Muzer]

Can someone point me towards the sort of thing I need, then, or at least give me the name? I'm slightly confused...

 

[Zetr0]

@Muzer

My friend, I do doubt that this is Aluminium, its more likely copper foil - which is readly available and cheap -

now, heres what I recommend


Copper Adhesive Tape £3.99 + Free PnP (eBay.co.uk BIN)


I use this a lot in creating pads and channels =)

Since its 30mm wide and 4 meters long its enough to do a fair few keyboards, I suggest that splitting the strip down the middles giving you 15mm each side and cutting at 15mm (1.5cm's) in length giving you a 15mm square - then stick on the bottom of the pads remember to clean the pads of the keys properly and make sure there no dirt-oil or grease so the adhesive on the back of the tape adheres propely =)

there.... job done --- oooh -- remember to take lots of pics =)


FYI for buddiest solder'ers out there - this stuff happily takes soldering between 180c - 260c as well =)

 

[Muzer]

It doesn't look very copper-like (the pads that haven't rubbed off are silver, though you can't really see that in the picture) - but whatever works is fine

 

[Merlin]

@ muzer

Zetr0's suggestion will work. It's probably going to work better than the original setup too, as copper is a much better conductor.

Nice find that, Zetr0!